US2667741A - Fuel injection and burner system for reactive propulsion power plants - Google Patents

Description

Feb. 2, 1954 N. C. P FUEL INJECTION AND BUR REACTIVE PROPU @riginal Filed Aug. 25 1946 RICE NER SYSTEM FOR LSION POWER PLANTS 2 SheetsSheet l Agent Feb. 2, 1954 N. c. PRICE FUEL INJECTION AND BURNER SYSTEM FOR REACTIVE PROPULSION POWER PLAN 2s, 194e 2 Sheets-Sheet 2 Original Filed Aug.

'2 INVENToR.

NATHAN C. PRloE BY Agent Patented Feb. 2, 1954 FUEL INJECTION AND BURNER SYSTEM FOR REACTIVE PROPULSION POWER PLANTS Nathan C. Price, Los Angeles, Calif., assignor to Lockheed Aircraft Corporation, Burbank, Calif.

Original application August 23, 1946, Serial No.

692,423, now Patent No. 2,540,594, dated February 6, 1951.

Divided and this application November 1, 1947, Serial No. 783,536

7 Claims. (Cl. 60-35.6)

This invention relates to reactive propulsion engines, such as ram jet power plants, and relates more particularly to fuel injection devices for burners for this general class of engines. lt is a general object of the invention to provide a practical, effective burner means of this type capable of maintaining an efcient combustion of the fuel.

This application is a division of my co-pending application, Serial No. 692,423, led August 23, 1946, now Patent No. 2,540,594, dated February 6, 1951.

In power plants of the above mentioned type the fuel is injected into a combustion chamber to burn in the high pressure relatively high velocity air stream which ows through the chamber. In order to obtain eicient power plant operation it is necessary to inject the fuel in a manner to eifect its substantially complete combustion and to preserve a distributed and yet somewhat confined llame throughout the various speeds of the power plant.

It is another object of the present invention to provide a fuel injection system of the class referred to which effects thorough thermal vaporization of the fuel and then introduces the fuel vapor into the combustion chamber at a multiplicity of shielded injection orifices designed and arranged to effect a uniform dispersion of the vaporized fuel across the air stream flowing through the combustion chamber. The Vaporizing and injecting means are constructed and arranged to preserve maintained flame propagation and ecient fuel combustion at the various speeds of operation of the power plant.

It is another object of the invention to provide a fuel burner for use in power plants of the class mentioned, comprising a multiplicity of fuel vapor injectors constructed and arranged to inject the fuel vapor in spaced concentric annular series occupying one or more transverse planes of the combustion chamber to obtain adequate distribution of the resultant flame and to effect substantially complete combustion of the thoroughly vaporized and well-distributed fuel.

A further object of the invention is to provide a fuel vapor burner system of the type referred to in which the individual vapor injectors are related to produce annular flames and yet are supported for free, independent thermal expansion and contraction.

A still further object of the invention is to provide a fuel vapor burner system of the character described embodying a simple, effective means for starting or initiating the burning of the fuel vapor at the several annular rows of injectors. A

2 single electrical igniter is arranged to cause a flame to be propagated with travels to the several injectors of each annular row to initiate fuel Vapor burning at all of the injectors.

Other objects and features of the invention will become apparent from the following detailed description of a typical preferred embodiment throughout which description reference is made to the accompanying drawings wherein:

Figure 1 is a longitudinal section of a ram jet power plant embodying the invention, showing certain parts in side elevation;

Figure 2 is an enlarged fragmentary sectional View of the fuel pump and turbine for driving the same;

Figure 3 is an enlarged transverse detailed sectional view taken as indicated by line 3 3 on Figure 1 illustrating the burner means;

Figure 4 is an enlarged fragmentary sectional View taken substantially as indicated by line 4 4 on Figure 3;

Figure 5 is a fragmentary perspective view of the fuel vapor injecting means;

Figure 6 is an enlarged fragmentary sectional View of a portion of the fuel vaporizing means; and

Figure '7 is an enlarged fragmentary sectional View of another portion of the Vaporizing means.

In the drawings I have shown the fuel vaporizing and injecting system of the present invention incorporated in a ram jet power plant of the class disclosed in my co-pending application identified above. The power plant includes a tubular body or shell A provided at its forward end with an inlet ram Il of the supersonic type and provided at its rear end with a propulsive nozzle I3. -The air compressing action of the inlet l l is controlled by the movable needle B in the inlet passage. The rear portion of the needle B telescopes over a stationary island C supported in the inlet portion of the shell A by streamlined struts 41. The nozzle i3 for producing the propulsive jet of combustion gases and air has a restricted throat 23 and is controlled by an axially movable throat member !98 carried by a censhroud 69 arranged around the rear portion of the island C. The major intermediate section l2 of the shell A extending between the ram inlet Il and the nozzle I3 is substantially cylin drical and forms the combustion chamber for 5 the power plant.

arranged within the stationary island C. The pump 62 is of the centrifugal type and its inlet or low pressure side is connected with an elbow 8|. fuel supply pipe 8U which extends outwardly through one of the hollow struts 41 to a suitable fuel supply not shown. The shaft 64 of the pump? 62 is carried by spaced bearings 65 and an/air turbine wheel 13 is fixed to the shaft.; The abovementioned shroud 89 is spaced'around the rear portion of the island C to leaveanannular air passage 10. The passage .receives'a'portionrof the rammed compressed ainfrom Ythe.inlet.|| and the air stream flowing through'the passage 10 acts upon blading on therturbine wheel 13 to drive the turbine. The air turbineinzturn drives the fuel pump 62. The high pressure side of the fuel pump 62 `delivers the fuel under prese sure to pipes 63 extending outwardly and rearwardly through the strutsA 41.r K

The vaporizing means-of' thefuelssystem is associated with thevcombustion-chamber: |2;to utilize the heat of" combustion to vaporizezthe fuel before it is delivered to the injecting means. The lines 63 from the pump |2llead through' .the

struts 41 to an annular andtubular header 14` engaged within 'the shell section I2," see 'Figures 4 and 6. A similar header 15 is 'arranged rearwardly of the header 14andthe -two header members are preferably substantially-squarein transverse cross section; A third manifold ring-or header 16 of similar configurationx is secured in the rear portion of :the combustion' chamber section I2 as shown in Figure 7. circumferentially spaced vaporizing tubes llhave their forward ends inA communication with the fuel supply header 14 and: passf rearwardly through openings'infthe wallsI of the adjacent header 15. The tubes lllcontinue-rearwardly in spaced adjacent relation to the wal1`of the com'- bustion chamber'section' I2" and have their rear ends receivedin openingsA in the'wall ofthe rear header 1B. A similar set' of vaporizing tubes 18 have their forward ends in communication with the fuel receiving header and their rear ends are in communication with the rear header 18. The tubes 11 and 18"a're"preferably alternated in a single annular series as illustrated. Fuel supplied to the header 14 by the pump 62 flows rearwardly through the tubes 11 and then forwardly through the tubes 18 to the header 15. During this circuit the'fuel is effectivelyvaporized. The tubes 'Il and 18 and the'manifolds 14, 15, and 16 are preferably formed of corrosion and heat resistant material such as Inconel.'

The fuel vaporized in the tubes 11 and 18 is delivered to vapor injection devices arranged in the forward portion or entrance ofthe combustion chamber. These devices are best illustrated in Figures 3, 4, 5 and 6. A plurality of circumferentially spaced tubular st'rutsor bars 8| ex"- tend radially inward from the vapor header 15 and are spaced between the supporting struts 41. Partitions 82 in the rear portions of the struts 41 define vapor passages 83 therein. The inner wall of the tubular vapor header 15 has spaced ports 24 which communicate with the interiors of the bars 8| and passages 83 to deliver vapor thereto for inward flow to the injectors.

The injectors comprise what I will term cup strips 84 arranged on the bars 8| and struts 41. The cup strips 84 are preferably arranged in concentric radially spaced annular rows as shown in Figure 3, and although the strips may be pro- The elbow |5| in turn communicates-with a:

A series ofv vided in two or more spaced transverse planes, I have shown all of the strips in a single transverse or diametric plane. The cup strips 84 are ycurved orarcuate andare substantially U- shaped in transverse cross sectiony having curved forward end walls and spaced substantially parallel or concentric side walls which extend rearwardly relative to the direction of air flow. As shown in the drawings, the cup strips 84 are secured-intermediate their ends to the struts 41 andbars 8| so that their side walls extend freely beyond the-struts and bars, both in the rearward and circumferential directions.

Each circular row of cup strips B4 embodies a multiplicity of the strips related to have their ends in spaced adjacent relation whereby their interiors are, in effect, in communication but the individual strips are free for independent thermal expansion and contraction. The several circular rows of cup strips 84 are spaced andrelatedias shown in-.F'igure V sothat the outer;

row is adjacent the wall of the shellA, andthe; inner row is in spaced surrounding relation to;

The vaporizingstrips are securedto the struts 41Y and bars 8|.

the above described shroud 89.-

by welding, or'the like,v so as to be rigid and stationary. Ports 85 are provided in the wallsofx.

the bars 8| and struts 41 to deliver fuel vapor to the interiors of the cup strips 8,4, and the innery ends of the bars and passages 83'are open toV the innermost strips. flows circumferentially in the cup strips and moves axially or downstream. In order to pre. vent stagnation of the vapor in the strips 34, andl to assure a more complete and uniform combus. tion ofthe vapor by means of controlled primary combustion, I provide a series of spacedY ports or,` openings 86 in or adjacent the forward wallsoff the strips. The capacity, location and spacing. of,- these openings 88.. are such that the flames arel not extinguished by the air admitted by them into the interiors of thecupA strips. Itl will be seen that the vapor., injecting means provides-and maintains an extensive and'uniforrn dispersion of.'

through a boss 81 on the shell A and passes in.

Wardly through openings in the shell and header- 15 to project into one of the hollow bars BI. The resistance wire of the glow plug for igniting the fuel is housed in a perforate shield 88. A liquid fuel line 89 enters the shell A and has a jet 98 directed to impinge a stream of fuel against the shield and glow plug. A short tap or pipe 9| leads from the interior of the liquid fuel header 142, and is arrangedV to direct a smallV stream of fuel against the shield and glow plug. A flame initiated at the glow plug travels out through the bar 8|, and the openings 85, and progresses through the several cup strips 84 to ignite the fuel in the strips. In practice, fuel from the pipe 9| will usually be employed to start the engine. However, in the case of certain fuels of low inflammability, and under difficultV starting conditions, additional fuel or special fuel may be supplied through the jet 9|! to assist in starting.

The fuel vaporizing and injecting means serve to preserveY a substantially constant air-.fuel ratio.'

irrespective of the altitude and translatory speed This vapor travels or-v The of the engine, the centrifugal pump 52 driven by the rammed air supply through the medium of the turbine 'it serving to maintain this ratio. The fuel pump S2 and turbine are designed and related to provide a given air-fuel ratio, for example, a ratio of approximately 18 to 1. During power plant operation, the liquid fuel is thoroughly vaporized during its passage through the tubes 'il and 'is and is efficiently burned upon admission to the high pressure and substantially constant pressure combustion chamber I2. The vaporization of the fuel increases the over-all efficiency of the power plant by a regenerative action and the evaporizing tubes carrying the fuel protect the walls of the combustion chamber section l2.

In considering the operation of the power plant, it may be assumed that the engine is to be associated with an air borne missile or aircraft to form a propulsive means therefor and that the missile or aircraft carries the fuel supply and the controls for the starting system, etc. The missile or aircraft is brought up to or beyond the speed of sound by other propulsive means, for example, by rocket power or turbo-jet propulsive devices. It is at this speed or above the speed of sound that the ram jet unit becomes efficient as a propulsive means. To start the engine current is supplied to the glow plug 92 and fuel is supplied to either the main fuel line @i3 or the starting jet te or both. Air flow through the annular passage Ie operates the air turbine 'i3 which in turn drives the pump 62 to supply the fuel to the vaporizing means. The fuel flows through the tubes i1 and i8 to the struts il and bars 8l and a small stream of the fuel is d'mcharged against the glow plug SI2 by the jet e@ or pipe 9|. The fuel is ignited at the glow plug 92 and as described the flame progresses through the adjacent bar 3| to the several annular series of cup strips Sil to provide flame at the several cup strips. The fuel employed may be gasoline, coal oil or other appropriate liquid fuel. After flame propagation is initiated at the cup strips ed, the fuel vapor continues to travel or flow circumferentially in the cup strips and moves axially or downstream from the strips. The spaced openings 8d admit sufcient air to the strips t@ to prevent stagnation of the fuel vapor and to obtain a complete uniform combustion of the vapor. However, the capacity and arrangement of the openings 85 are such that the flames are not extinguished by the air admitted through them. The fuel vapor burner embodying the annular series of cup strips fifi provides and maintains a substantially uniform dispersion of the fuel vapor across substantially the entire air stream of the power plant. The effective distribution of the fuel at the entrance portion of the combustion chamber i2 assures efficient operation of the power plant. The several cup strips mounted as described above have individual freedom of thermal expansion and construction both in the circumferential di rection and the radial direction. This is important in preventing distortion of the burner parts.

Having described only a typical preferred form of my invention, I do not wish to be limited to the particular details set forth, but wish to reserve to myself any features or modifications that may fall within the scope of the following claims I claim:

l. In a reactive propulsion engine, a corn'ous1 tion chamber, means for supplying air under pressure to the entrance of the combustion charnber, a propulsive nozzle at the exit of the combustion chamber, fuel supply means, and Vaporizing and injecting means receiving fuel from the supply means and. injecting fuel vapor into the combustion chamber, the last named means including circumferentially spaced tubular members extending radially into the entrance portion of the combustion chamber and conducting fuel from the supply means, and arcuately curved radially spaced cup strips secured intermediate their ends to the members to receive fuel therefrom, the cup strips having spaced generally concentric imperforate side walls, perforate upstream walls and having open sides facing downstream.

2. In a reactive propulsion engine, a combustion chamber, means for supplying air under pressure to the entrance of the combustion chamber, a propulsive nozzle at the exit of the combustion chamber, fuel supply means, and Vaporizing and injecting means receiving fuel from the supply means injecting fuel vapor into the combustion chamber, the last named means including circumferentially spaced tubular members extending substantially radially inward in the entrance of the combustion chamber and conducting fuel from the supply means, and radially spaced arcuate cup strips secured intermediate their ends to the members and arranged to form radially spaced circular series of the strips, said cup strips having communication with their respective tubular members to receive fuel therefrom and having their open sides facing downstream, the cup strips having spaced concentric imperforate side walls and upstream wall portions joining the side walls, the upstream wall portions of the cup strips having circumferentially spaced air admitting openings.

3. In a reactive propulsion engine, a combustion chamber, means for supplying air under pressure to the entrance of the combustion chamber, a propulsive nozzle at the exit of the combustion chamber, fuel supply means, vaporising means receiving fuel from the supply means, fuel injecting means including tubular members receiving the vapor from the vaporizing means and extending into the combustion chamber, channel strips secured intermediate their ends to the members to have their ends free and to have their interiors in communication with the members, the free ends of the strips on adjacent members being in spaced adjacent and aligned relation so that the interiors of the strips are in communication, and means associated with one of the tubular members for igniting the fuel vapor in the several strips.

4. In a reactive propulsion engine, a combustion chamber, means for supplying air under pressure to the entrance of the combustion chamber, a propulsive nozzle at the exit of the combustion chamber, fuel supply means, Vaporizing means receiving fuel from the supply means, fuel injecting means including tubular members receiving the vapor from the vaporizing means and extending into the combustion chamber, channel strips on the members having their in- Jneriors in communication with the members to receive the fuel vapor therefrom, the interiors of the strips on the several members being in communication one with the other, an igniter at one of the tubular members for igniting fuel therein, and means for supplying fuel to the igniter to initiate combustion of said vapor in the several channel strips.

5. In a Yreactive propulsion engine, a combustionl chamber, means for supplying air under pressure to the entrance of the combustion chamber, a propulsive nozzle at the exit' of the combustion chamber, fuel supply means, Vaporizing means receiving fuel from the supply means, fuel injecting means including tubular members receiving the vapor from the vaporizing means and extending into the combustion chamber, channel strips on the members having their interiors in communication with the members to receive the fuel vapor therefrom, the interiors ofthe strips on the several members being in communication, a glow plug in one of the tubular members, and means for jetting fuel from the supply means to the glow plug to initiate combustion of said vapor in the channel strips.

6. In a reactive propulsion engine, a combustion chamber, means for supplying airY under pressure to the entrance of the combustion chamber, a propulsive nozzle at the exitof the combustion chamber, fuel supply means, vapor` izing means receiving fuel from theY supply means, -fuel injecting means including tubular' members receiving the vapor from the vaporizing strips on the several members being in communi' cation, a glow plug in one of the tubular members, and a jet for discharging starting fuel at' the glow plug to initiatei'combustion of the vapor at the channel strips.

7. A vreactive propulsion engine comprising a tubular air receiving and conducting shell, a por-` tion of the shell constituting a combustion chamber, a plurality of circumferentially spaced fuelV conducting members extending substantially radially into the chamber, andradially spacedv f strips having imperforate generally parallel side walls and being arranged with their open sides facing downstream with relation to the combustion chamber, there being spaced air-admitting openings in the upstream'wallsof the strips.

References Cited in the file of this patent UNITED sTATEs PATENTS Number Name Date 1,405,482 Bostedo Feb. 7, '1922 1,601,863v Leins Oct. 5, 1926 1,725,914 Hallowell Aug. 27, 1929'` 2,114,738 Heller et al Apr. 19, 1938 2,326,072 Seippel Aug. 3, 1943 2,385,833 Nahigyan Oct. 2, 1945 2,417,445 Pinkel Mar. 18, '1947l 2,438,247 Knudsen Mar. 23, 1948 2,479,776 Price Aug. 23, 1949' 2,502,332 McCollum Mar. 28, 1950 2,503,006 Stalker Apr. 4, 1950 OTHER REFERENCES Gas Turbines and' Jet Propulsion, by G. Geoffrey emita-'1944 (Fig. 23)..

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